Volatile Organic Compound Gas-Sensing Properties of Bimodal Porous α-Fe₂O₃ with Ultrahigh Sensitivity and Fast Response

Abstract

Porous solid with multimodal pore size distribution provides plenty of advantages including large specific surface area and superior mass transportation to achieve high gas-sensing performances. In this study, α-FeO nanoparticles with bimodal porous structures were prepared successfully through a nanocasting pathway, adopting the bicontinuous 3D cubic symmetry mesoporous silica KIT-6 as the hard template. Its structure and morphology were characterized by X-ray diffraction, nitrogen adsorption-desorption, transmission electron microscopy, and so on. Furthermore, the gas sensor fabricated from this material exhibited excellent gas-sensing performance to several volatile organic compounds (acetone, ethyl acetate, isopropyl alcohol, n-butanol, ethanol, and methanol), such as ultrahigh sensitivity, rapid response speed (less than 10 s) and recovery time, good reproducibility, as well as stability. These would be associated with the desirable pore structure of the material, facilitating the molecules diffusion toward the entire sensing surface, and providing more active sensing sites for analytical gas.

Highly responsive and selective ppb-level NO2 gas sensor based on porous Pd-functionalized CuO/rGO at room temperature

“…13,28 Furthermore, the paramagnetic properties of CuO, the number of chemisorbed oxygen species, the oxygen-vacancy site of the materials and the dipole moment of gas molecules are also possible factors for determining gas selectivity to a certain extent. 52,53 A noticeable character of long-term stability for a gas sensor is another crucially important role in practical applications. In Fig.…”

Efficient Conversion of Benzyl Alcohol on a Mesoporous Co3O4

“…To date, some metal-based materials played a more and more important role in heterogeneous catalysis, such as Fe-based, Co-based, and Ni-based catalysts. It has been demonstrated that mesoporous metal-based materials possess widely applications owing to the large superficial area and porosity, which were widely used as microwave absorbers, electrode materials, , sensors, , and catalysts, − etc. Over the course of the decades, lots of mesoporous silica materials were synthesized. , Inspired by ordered mesoporous silica materials, some ordered mesoporous metal oxides were successfully synthesized even if huge challenges exist.…”

Doping-free bandgap tunability in Fe2O3 nanostructured films

“…28,29 Iron oxide is widely used in a wide range of applications in nanodevices due to its unique properties, such as water splitting, 24,25,30 supercapacitor, [31][32][33] lithium-ion battery, [34][35][36] catalyst, [37][38][39] photodetectors, 40 and gas sensor. [41][42][43] In our proposed approach, we synthesized Fe2O3 nanostructured films on ITO/glass substrates at various synthesis temperatures. The results show that Fe2O3 nanostructured films contain two mixtures of Fe 2+ and Fe 3+ cations and two trigonal (α) and cubic (γ) phases.…”